<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>array</title>
    <script>
        //定义数组
        let a1 = ["a", "b", "c"];
        let a2 = [1, 2, 3];
        a3= a1.concat(a2);
        //输出
        document.write(a1 + "<br>");
        document.write(a2 + "<br>");
        //for遍历数组
        for(let i =0;i<a3.length;i++){
            document.write(a3[i]+"<br>")
        }
    </script>
</head>
<body>

</body>
</html>